Rock drilling tool



July 23,1957 G. M. DlcK 2,800,303

Rocx DRILLING TooL Filed May 12, 195s INVENTOR GEORGE M. DICK HISATTORNEY United States Patent ROCK DRILLING TOOL George M. Dick,Sherbrooke, Quebec, Canada, assignor to Ingersoll-Rand Company, NewYork, N. Y., a corporation of New Jersey Application May 12, 1953,Serial No. 354,606

4 Claims. (Cl. Z55- 64) This invention relates to cutting implements,and more particularly to a rock drilling tool having cleansing fluidpassages therein arranged to direct the flow of cleansing iluid radiallyoutward along the cutting edge of the tool.

Conventional drilling tools of the type to which this inventionappertains are normally provided with a centrally located cleansingfluid passage arranged in such a manner as to direct the flow ofcleansing fluid longitudinally away from the cutting face of the tool.The fluid thus directed impinges on the surface of the rock beingdrilled and is deflected radially outward and washes rock cuttings backalong the drill hole between the boundaries of the hole and theperiphery of the tool. With this type of cleansing, maximum cleansingoccurs at the central portion of the tool and is reduced proportionatelyin a radially outward direction. This cleansing distribution issatisfactory when the rock being drilled is relatively soft, howeverwhen the rock being drilled is relatively hard, then a reversedistribution is desirablethat is, maximum cleansing should occur at theperiphery of the tool. This is so because in such rock, tine rockparticles or cuttings between the side surface of the tool and thesurface of the drill hole act as an abrasive compound which grinds awaythe peripheral surface of the tool thereby reducing the gauge of thetool.

It is accordingly one object of this invention to eliminate excessivewear of the gauge surfaces of a drilling tool by insuring continuedcleansing of these surfaces of rock cuttings.

A further object is to construct a rock drilling tool provided withcleansing uid passages terminating in and olf-center of the cutting faceof the tool and arranged to direct cleansing fluid along a path leadingforwardly along tne cutting surface of the tool and also toward theperipheral surface of the tool.

Further objects of this invention will become apparent from thefollowing specification and drawings in which Figure 1 is an end view ofa drilling tool constructed in accordance with the practice of thisinvention,

Fig. 2 is a side View of Figure 1, partly in section, taken along theline 2 2 looking in the direction of the arrows, and

Fig. 3 is an end view of a modified form of the invention.

Referring to the drawings and at first to the form of the inventionshown in Figures 1 and 2, the numeral 10 designates a drilling toolconstructed in accordance with the practice of the invention andcomprising a body 11 of frusto-conical shape that may be an integralportion of a drill rod or a separate member (as shown) adapted forattachment to a drill rod in a well known manner. Formed within the body11 is a centrally located passage 12 for conducting a cleansing uid tothe cutting face of the tool for washing cuttings from the surface ofthe rock being drilled. In furtherance to this end, the passage 12 isprovided with branch passages 13which terminate in the cutting face ofthe tool at points radially displaced from the center of the body 11 andhaving N 2,800,303 ICC Patented July 23 1957.

their outlet ends positioned to direct the flow of cleansing fluid alongthe cutting surface of the tool and toward the front end and theperiphery of the tool 10. With this arrangement the cleansing fluid isdirected at the gauge surfaces aty the periphery of the tool therebykeeping these surface areas relatively clean and preventing excessivewear at such areas.

The drilling tool shown by way of illustration only is of the four-pointtype and accordingly the body 11 is provided with four equi-angularlyspaced wings 14 that are separated by grooves 15 extendinglongitudinally of the body for the escape of cuttings from the surfaceof the rock being drilled. Formed in the wings 14 are diametric slots 16that lie at right angles to each other and extend along the wings to theperiphery of the body 11. The slots 16 are of uniform width throughouttheir lengths and their opposed side surfaces lie at right angles to thebottom surfaces. Positioned within the slots 16 are hard metal insertsserving as cutters.

As viewed in Fig. 2 there is a vertical cutter and a horizontal cutter.Each cutter extends transversely of the bit having its axis on a linepassing through the approximate center of rotation of the tool and issubstantially straight along its longitudinal axis. In the particularform of the invention shown by way of illustration, each cutter is madeup of two cutter sections 17 having their inner ends spaced apart. Theforward marginal portions of the cutter sections 17 protrude from theslots 16 and are bounded by surfaces 19 inclined forwardly relative toeach other and relative to the longitudinal axis of the bit to form awear resisting cutting edge 18 at the intersection of such surfaces 19.

The cutter sections 17 are bonded to the body in any well known manner,as for example by brazing to secure the cutters xedly to the body.

Means are provided for preventing the cutter sections 17 from beingshifted endwise in the slots 16. To this end the body is provided with arecess 20 at the inner ends of the slots 16 and a rigid tubular abutmentmember 21 is positioned in the recess 20 abutting the inner ends of thecutters.

An opening 22 in the abutment member 21 is arranged coaxially with andforms an extension of the central cleansing liuid passage 12. Theupstream ends 23 of the branch passages 13 are located at pointsupstream of the downstream end 24 of the central passage 12, and thedownstream ends of the branch passages are located in the surface of thebody 11 at points off-center from the central passage 12. In furtheranceto the end that cleansing fluid emanating from the branch passages 13serve to clean the cutting edges 18 and gauge surfaces (exposed ends) ofthe inserts, a branch passage 13 is provided for each insert, four inthe form of the invention illustrated. Each passage 13 extends in adirection radially outward and frontwardly (relative to the body 11)from the passage 12 to a point near the periphery of the body thenradially inward and frontwardly and at an angle, in the transverseplane, to the inlet portion, and terminating in the face of the body 11.The outlet, or terminal, ends of the passages 13 are arranged around theface of the tool such that a jet of cleansing fluid is directed at theleading inclined surface 19 of the cutters. For example, assumingclockwise rotation of the tool shown in Fig. 1, the mouth of the passage13 associated with the lower leading end portion of the vertical cutter(the lowermost cutter section 17 is located adjacent the succeedingclockwise cutter section 17 (left horizontal). Thus cleansing uidemanating from this particular branch passage is directed at the lowerend portion of the lower left surface of the vertical cutter-ie., theleft inclined surface 19 of the lowermost cutter section 17, as viewedin Fig. 1. The reason for directing cleansing iluid along the-leading,`rather than the'trailing, cutting surface is that dueto the-sweeping-actioneof the -tool, andwhich-is rotated by a rock drill between blowsof its percussive element against the tool, ,the probability of aquantityrof roclfcntti'ng'sy gathering` at the leading' inclinedYsurface;

tion land-inclined` slightly itoward 'the leading side surface' 19' of'the'cutting'edge (see'dottedflowpathFig. 2) andl sothatsuclrilow' isdirectedlboth. forwardly to` the cutting end' ancl` towardtheperipheryof the tool (seeI dotted flow path-Fig.v 1')-`. Withthesparticularformof/'the invention illustrated iir'Figs; 1 and-2 cleansing fluid isconductedtothe Viaceiofrth'e tool through both central andY sidepassages. Thus this tool isadapted'for use in both hard and'softrockdrilling.v Irrdrillinghard Arock or similar-rock^ formationsonly, itmaybe desirableto block olfA the central uid passage' 12 irrordertoincrease'the` ow rate of cleansing uidthroughthe off-center'passages 13.This Lconstruction'isillustrated: in Fig. 3 `whichis identical in"allrespectsv withY theV previously described Vforrn of theinventiorrwiththeA exception that a solidplug 25 replacesthe-tubularabutrnent'member 21, which plug serves as anabutment memberforA thecutters'and to block offl flow-th'rough'the4 centralpassage 12'to the face of the tool:

IY claim:

1. Ar-rotatable -percussive V'type vdrillingtool having a body, a cuttermountedftransversely on` anend ofthe body and having itslongitudinal`axis `orla` line `passing vthrough the approximate center ofrotation'of Ithe tool, said cutter having its forward marginal portion bounded bysurfaces forwardly inclined toward each other and the longitudinal axisof said Vbody to Vforma cutting edge at their`l intersection, acleansing uid passage extending longitudinally inthe lb'itandterminatingin said end thereofand' displaced^to the sideof said cutter 'having aleading surface portion, relative to the directionof rotation of theYtool, the terminating end portion of saidk passage beingjpositioned todirect cleansing 4lluid` on allow path leading forwardly along anintermediate section of such leading surface portion and directedoutwardly along such surface portion.

2. The drilling tool claimed in claim 1 in which an additional cleansingiluid passage is provided in the body leading longitudinally therein andterminating in said end of the body at a point'spaced from said cutterand having its terminating end portion positioned to direct cleansingfluid axially forward of said tool.

3i The drilling tool claimed in claim 1 inV which said cutter is formedin two parts having their inner ends spaced apart at the approximatecenter of rotation of said body with a cleansing uid passage providedfor each part, and in which an additional cleansing Huid passage isprovided terminating in said end of the body between the inner ends ofsaid parts and having such terminating end portion formed to directcleansing uid axially of said tool.

4. A' rotatable percussivetype drilling tool having a body, latleast'onctransverse cutter on one end of the body having portions located-onopposite sides. of the approximate center ofl rotation of the tool, suchcutter portions having-1their'forwardmargins bounded by inwardlyinclined"surfaces forminga cutting edge at their intersection;`a'llongitudinal cleansing iluid passage in said bodyterminatingfin"said'endof. the body ata point displaced' from-*thecutter and having its terminating end portion formed todirectthe'ow ofcleansingy uid along a flow path' leading'forwardlyfalongy the surfaceof an intermediateV section of the end part of each inclinedsurface`which'leads, relative to the direction of rotation,thecoterminous portionl of the other'. part and directed radiallyoutward 'towardftheperiphery ofthe body, there beingnone suchpassage'foreach such'lead portion.

ReferencesCtedin the -file of this patent UNITED STATES PATENTSRe.20,468- Brenholm` May 12, 1936 1,444,305 Christian Feb. 6, 1921,476,481. Bashara'et al Dec. 4, v1923 2,103,359- Graham Dec. 28, 19372,201,570 Zublinn May 2l, 1940 .2,557,835 Leissler Sept. 12, 1944 vFOREIGN PATENT S 652,562 Great Britain Sept. 30, 1948

